Acylaminoaryloxy and arylthio pyrimidines as herbicides

ABSTRACT

As new compounds, acylaminoaryloxy and arylthio pyrimidines having the formula ##STR1## wherein A is oxygen or sulfur; M is CH or N; X is hydrogen, lower alkyl, halo, methoxy, alkoxy, C 1  -C 3  alkylthio, cyano, carbomethoxy or trifluoromethyl; ##STR2## wherein R&#39; is C 1  -C 8  straight, branched-chain or halo-alkyl, aryl; and R is hydrogen, C 1  -C 8  straight or branched chain alkyl, C 5  or C 6  cycloalkyl or aryl.

This application is a continuation of Ser. No. 06/789,279 filed Oct. 18,1985, now abandoned.

BACKGROUND OF THE INVENTION

The present invention relates to certain acylaminoaryloxy pyrimidinesand acylaminoarylthio pyrimidines which are particularly useful aspost-emergent herbicides against annual and perennial grasses andbroadleaf weeds.

Herbicides are widely used by farmers, commercial agriculturalcompanies, and other industries in order to increase crop yields forsuch staple crops as corn, soybeans, rice, and the like, and toeliminate weed growth along highways, railroad rights-of-way, and otherareas. Herbicides are effective in killing or controlling unwanted weedswhich compete for soil nutrients with the crop plants, and by reason ofthe fact that they kill weeds, are responsible for improving theaesthetic appearance of highway and railroad rights-of-way.

There are a number of different types of herbicides presently soldcommercially, and these fall into two general categories. The categoriesare pre-emergence and post-emergence herbicides. The pre-emergenceherbicides are normally incorporated into or applied to the soil priorto the emergence of the weed plants from the soil, and thepost-emergence herbicides are normally applied to plant surfaces afteremergence of the weeds or other unwanted plants from the soil.

THE PRIOR ART

The prior art contains numerous examples of pyrimidine-based compoundswhich have been disclosed to be herbicidally effective against a varietyof weed pests. Examples of such prior art references include U.S. Pat.Nos. 4,001,234 and 4,427,437.

Still other patents, i.e., European patent application Publication No.0,001,187, discloses 2-phenoxy and 2-phenylthio pyrimidine compoundsuseful as pre-emergent and post-emergent herbicides. In addition, U.S.Pat. No. 3,126,271, Tomson et al., also relates to certain pyrimidinecompounds and to a method of controlling weeds with the use of thesecompounds.

Efforts are constantly being made, however, to find compounds which areequal to or greater in effectiveness than presently existing compounds,or which are more economical to produce.

DESCRIPTION OF THE INVENTION

It has now been discovered that certain new and novel acylamino aryloxyand acylaminoarylthio pyrimidines have good herbicidal and plant growthregulating activity, particularly when applied as post-emergentherbicides and used against annual and perennial grasses, and broadleafweed pests.

As used herein, the term "herbicide" means a compound or compositionwhich controls or modifies the growth of plants. By the term"herbicidally effective amount" is meant any amount of such compound orcomposition which causes a modifying effect upon the growth of plants.By "plants" is meant germinant seeds, emerging seedlings and establishedvegetation, including roots and above-ground portions. Such controllingor modifying effects include all deviations from natural development,such as killing, retardation, defoliation, desiccation, regulation,stunting, tillering, leaf burn, dwarfing and the like.

The new and novel compounds of this invention are acylaminoaryloxypyrimidines and acylaminoarylthio pyrimidines.

These compounds have the formula ##STR3## wherein

A is oxygen or sulfur;

M is CH or N;

X is hydrogen, lower alkyl, halo, methoxy, alkoxy, C₁ -C₃ alkylthio,cyano, carbomethoxy or trifluoromethyl; ##STR4## wherein

R' is C₁ -C₈ straight, branched-chain or halo-alkyl, aryl; and

R is hydrogen, C₁ -C₈ straight or branched chain alkyl, C₅ or C₆cycloalkyl or aryl.

These compounds have been found to have especially good herbicidalactivity against broadleaf weed pests when applied as a post-emergentherbicide. They are also effective as pre-emergent herbicides and plantgrowth regulators, but not to the same extent as when appliedpost-emergent.

Preferred compounds include:

2,2-dimethyl-N-[4-[(4,6-dimethylpyrimidin-2-yl)thio]phenyl]pentanamide;

2-chloro-N-[4-[(4,6-dimethylpyrimidin-2-yl)thio]phenyl]butanamide;

2,2-dimethyl-N-[4-[(4,6-dimethylpyrimidin-2-yl)thio]-2-methylphenyl]propanamide;

2,2-dimethyl-N-[4-[(4,6-dimethylpyrimidin-2-yl)thio]phenyl] propanamide;

2,2-dimethyl-N-[4-[(4,6-dimethylpyrimidin-2-yl)thio]-3-fluorophenyl]propanamide;

N-[3-chloro-[4-(4,6-dimethylpyrimidin-2-yl)thio]phenyl]-2,2-dimethylpropanamide;

3-chloro-N-[4-[(4,6-dimethylpyrimidin-2-yl)thio]phenyl]-2,2-dimethylpropanamide;

N-[4-[(4,6-dimethylpyrimidin-2-yl)thio]phenyl]-2-methylpropanamide;

N-[4-[(4,6-dimethylpyrimidin-2-yl)thio]phenyl]-2-methylbutanamide; and

2,2-dimethyl-N-[4-[(4,6-dimethylpyrimidin-2-yl)oxy]phenyl]propanamide.

The compounds2-chloro-N-[4-[(4,6-dimethylpyrimidin-2-yl)thio]-phenyl]butanamide and2,2-dimethyl-N-[4-[4(4,6-dimethylpyrimidin-2-yl)-thio]phenyl]pentanamidehave rice selectivity. They control boardleaf and grassy weeds growingin and amongst the rice plants in a post-emergent application.

The preparation of the compounds of this invention is described below.

1. Oxygen Analogs

4,6-Dimethyl-2-chloropyrimidine is prepared according to the procedureof Marshall and Walker, J. Chem. Soc., 1004 (1951). The correspondingpyrimidinyloxyaniline is prepared by simple displacement of the reactive2-halogen by treatment with 4-aminophenol and potassium carbonate.##STR5##

The acylation of the aniline is carried out by treatment with an acidchloride, chloroformate, chlorothioformate or dialkylcarbamyl chlorideand a catalytic amount of 4-dimethyl-aminopyridine (DMAP) in pyridine.##STR6## wherein

R=R'=alkyl, branched alkyl, aryl, etc;

R=OR';

R=SR'; and

R=N(R')₂

The synthesis of mercaptopyrimidines has been reviewed in "The Chemistryof Heterocyclic Compounds", a series published by Interscience Publ.,New York and London, "The Pyrimidines", Vol. XVI of the series.Accordingly, 4,6-dimethyl-2-mercaptopyrimidine is prepared by condensingthiourea and 1,3-pentanedione in ethanolic hydrochloric acid. ##STR7##

Pyrimidinylthioanilines were prepared by displacement of halogen from anaromatic or heteroaromatic nitro compound with the mercaptopyridine andpotassium carbonate. Nitro compounds thus obtained are reduced toanilines by a standard procedure using iron and a catalytic amount ofhydrochloric acid in aqueous ethanol. ##STR8## wherein Y=F, Cl; andM--CH, N.

Acylation of pyrimidinylthioanilines are carried out as presented abovein the case of oxygen analogs.

N,N-disubstituted amides are prepared by treatment of an N-arylamidewith an alkyl halide in a two-phase mixture of benzene and 50% sodiumhydroxide using a catalytic amount of tetrabutylphosphonium bromide(TBPB). ##STR9## where Y=Cl, Br or I.

Ureas can be synthesized by treatment of an aniline with an isocyanatein dry methylene chloride using a catalytic amount of diazobicyclooctane(DABCO).

EXAMPLE 1 4,6-dimethyl-2-(4-nitrophenyl)pyrimidine

A solution of 25.0 grams (g) 4,6-dimethyl-2-mercaptopyrimidine, 25.1 g4-fluoronitrobenzene and 24.6 g potassium carbonate in 750 milliliters(ml) acetonitrile was refluxed for 16 hours. The solution was thenfiltered hot through a pad of dicalite. The dicalite was washed with 300ml hot acetonitrile. The solvent was evaporated from the combinedfiltrates giving a waxy yellow solid. This solid was triturated withhexanes giving 42.5 g yellow solid.

EXAMPLE 2 4-[(4,6-dimethylpyrimidin-2-yl)thio]aniline

A 250 ml 3-necked flask was equipped with mechanical stirrer, condensorand thermometer. To this was added in the following order: 4.6 g ironpowder, 50 ml water, 60 ml ethanol and 0.5 ml concentrated hydrochloricacid. The mixture was heated to reflux with a heating mantle. Theheating mantle was then removed and when the reflux subsided (temp about76° C.) a small portion of4,6-dimethyl-2-[(4-nitrophenyl)thio]pyrimidine was then carefully added.The rest of the 4,6-dimethyl-2-[(4-nitrophenyl)thio]pyrimidine, a totalof 7.1 g was added over a period of about one hour and the solution wasrefluxed for 5 minutes. The heating mantle was removed and thetemperature allowed to drop to 68° C. 0.5 g (4.08×10⁻³ moles) 50% sodiumhydroxide was added to the solution and vigorous stirring was continuedfor 5 minutes. The solution was heated to 75° and filtered through a padof dicalite. The dicalite was washed with 200 ml hot ethanol. Thecombined filtrates were stripped giving a tan solid. The solid wastriturated with water and dried in a vacuum drying oven. A light tansolid (5.9g) was obtained.

EXAMPLE 3 N-[4-[(4,6-Dimethylpyrimidine-2-yl)thio]phenyl]benzamide

A solution of 1.5 g 4-[(4,6-dimethylpyrimidin-2-yl)thio]aniline, 0.9 gbenzoyl chloride and about 0.1 g of 4-dimethylaminopyridine (DMAP) in 25ml pyridine was stirred for 16 hours at room temperature. The solventwas evaporated and the resulting yellow solid was partitioned between250 ml ethyl acetate and 150 ml water. The ethyl acetate solution wasthen washed with 2×150 ml water and dried over Na₂ SO₄. The solvent wasevaporated giving 2.0 g off-white solid, m.p. 190°-192° C. The structurewas confirmed by infrared, nuclear magnetic resonance and mass spectralanalysis as that of the desired product,N-[4-[(4,6-dimethylpyrimidin-2-yl)thio]phenyl]benzamide.

EXAMPLE 4 N-[4-[(4,6-Dimethylpyrimidin-2-yl)thio]phenyl]-N'-phenylurea

A solution of 1.5 g 4-[(4,6-dimethylpyrimidin-2-yl)thio]aniline, 0.8 gphenyl isocyanate an about 0.1 g diazobicyclooctane in 100 ml drymethylene chloride (passed through a column of neutral alumina) wasstirred for 16 hours at room temperature. The solvent was thenevaporated, giving 2.2 g off-white solid, m.p. 196°-200° C. Thestructure was confirmed by infrared, nuclear magnetic resonance and massspectral analysis as that of the desired product,N-[4-[(4,6-dimethylpyrimidin-2-yl)thio]phenyl]-N'-phenylurea.

EXAMPLE 5N-[4-[-(4,6-dimethylpyrimidin-2-yl)thio]phenyl]-N-methylhexanamide

Four grams N-[4-[(4,6-dimethylpyrimidin-2-yl)thio]phenyl]hexanamide, 3.4g methyl iodide and 0.4 g tetrabutylphosphonium bromide was dissolved ina mixture of 10 ml 50% NaOH and 50 ml benzene. This was stirredvigorously at room temperature for 72 hours. Fifty milliliters water wasthen added and the benzene layer was separated off. The benzene solutionwas washed with 4×100 ml water then dried over Na₂ SO₄. The solvent wasevaporated giving 3.5 g dark brown oil. The oil was chromatographed onsilica gel eluted with 50% ethyl acetate/hexanes giving 2.5 g yellow oilwhich slowly crystallized. Melting point of the resulting pale yellowwolid was 61°-63° C. The structure was confirmed by infrared, nuclearmagnetic resonance and mass spectral analysis as that of the desiredproduct,N-[4[(4,6-dimethylpyrimidin-2-yl)thio]phenyl]-N-methylhexanamide.

                  TABLE I                                                         ______________________________________                                         ##STR11##                                                                    Cmpd.                                                                         No.   A     M      X      Z               R                                   ______________________________________                                        1     S     CH     H                                                                                     ##STR12##      H                                   2     S     CH     H                                                                                     ##STR13##      H                                   3     S     CH     H                                                                                     ##STR14##      H                                   4     S     CH     H                                                                                     ##STR15##      H                                   5     S     CH     H                                                                                     ##STR16##      H                                   6     S     CH     H                                                                                     ##STR17##      H                                   7     S     CH                                                                                           ##STR18##      CH.sub.3                            8     S     CH     H                                                                                     ##STR19##      H                                   9     S     CH     H                                                                                     ##STR20##      H                                   10    S     CH     H                                                                                     ##STR21##      H                                   11    S     CH     H                                                                                     ##STR22##      H                                   12    S     CH     H                                                                                     ##STR23##      H                                   13    S     CH     H                                                                                     ##STR24##      H                                   14    S     CH     H                                                                                     ##STR25##      H                                   15    S     CH     H                                                                                     ##STR26##      H                                   16    S     CH     H                                                                                     ##STR27##      H                                   17    S     CH     H                                                                                     ##STR28##      H                                   18    S     CH     H                                                                                     ##STR29##      H                                   19    S     CH     H                                                                                     ##STR30##      H                                   20    S     CH     H                                                                                     ##STR31##      H                                   21    S     CH     H                                                                                     ##STR32##      H                                   22    S     CH     H                                                                                     ##STR33##      H                                   23    S     CH     H                                                                                     ##STR34##      H                                   24    S     CH     3-Cl                                                                                  ##STR35##      H                                   25    S     CH     H                                                                                     ##STR36##      H                                   26    S     CH     H                                                                                     ##STR37##      H                                   27    O     CH     H                                                                                     ##STR38##      H                                   28    S     CH     H                                                                                     ##STR39##      H                                   29    S     CH     H                                                                                     ##STR40##      H                                   30    S     CH     3-Cl                                                                                  ##STR41##      H                                   31    S     CH     2-CH.sub.3                                                                            ##STR42##      H                                   32    S     CH     H                                                                                     ##STR43##      H                                   33    S     CH     H                                                                                     ##STR44##      H                                   34    S     CH     H                                                                                     ##STR45##      H                                   35    S     CH     3-CH.sub.3                                                                            ##STR46##      H                                   36    S     CH.sub.3                                                                             H                                                                                     ##STR47##      H                                   37    S     CH     3-F                                                                                   ##STR48##      H                                   38    S     CH     H                                                                                     ##STR49##      H                                   39    S     CH     H                                                                                     ##STR50##      H                                   40    S     CH     H                                                                                     ##STR51##      H                                   41    S     CH     H                                                                                     ##STR52##      H                                   42    S     CH     H                                                                                     ##STR53##      H                                   43    S     N      H                                                                                     ##STR54##      H                                   44    S     N      H                                                                                     ##STR55##      H                                   45    S     CH     H                                                                                     ##STR56##      H                                   46    S     CH     H                                                                                     ##STR57##      H                                   47    S     CH     H                                                                                     ##STR58##      H                                   48    S     CH     H                                                                                     ##STR59##      H                                   49    S     CH     H                                                                                     ##STR60##      H                                   50    S     CH     H                                                                                     ##STR61##      H                                   51    S     CH     H                                                                                     ##STR62##      H                                   52    S     CH     H                                                                                     ##STR63##      CH.sub.3                            53    S     CH     H                                                                                     ##STR64##      H                                   54    S     CH     3-Cl                                                                                  ##STR65##      H                                   55    S     CH     2-CH.sub.3                                                                            ##STR66##      H                                   56    S     CH     2-CH.sub.3                                                                            ##STR67##      H                                   57    S     CH     N                                                                                     ##STR68##      H                                   58    S     CH     3-CF.sub.3                                                                            ##STR69##      H                                   59    S     CH     2-CF.sub.3                                                                            ##STR70##      H                                   60    S     CH     2-OCH.sub.3                                                                           ##STR71##      H                                   61    S     CH     2-OCH.sub.3                                                                           ##STR72##      H                                   62    S     CH     H                                                                                     ##STR73##      H                                   63    S     CH     H                                                                                     ##STR74##      H                                   64    S     CH     H                                                                                     ##STR75##      H                                   65    S     CH     H                                                                                     ##STR76##      H                                   66    S     CH     H                                                                                     ##STR77##      H                                   ______________________________________                                    

The herbicidal activity of the preferred compound of the invention asexhibited by means of tests in accordance with the following procedure.

EXAMPLE 2 Herbicidal Activity Tests

This example offers herbicidal activity test data to show theeffectiveness of the amide compounds of the invention. The effect isobserved by comparing the extent of weed control in test flats treatedwith the compounds against that occurring in similar control flats. Thesoil used in these tests was a sandy loam soil from the Livermore,California area.

Also added to the soil was 17-17-17 fertilizer (N-P₂ O₅ -K₂ O on aweight basis), amounting to 100 ppm by weight with respect to the soiland 200 ppm Captan, a soil fungicide.

The treated soil was then placed in flats which were 3 inches deep, 6inches wide, and 10 inches long. The soil was tamped and leveled with arow marker to impress six rows across the width of the flat. The testweeds were as follows:

    ______________________________________                                        COMMON NAME   SCIENTIFIC NAME   ABR                                           ______________________________________                                        GRASSES:                                                                      annual ryegrass                                                                             Lolium multiflorum                                                                              ARG                                           watergrass    Echinochloa crusgalli                                                                           WG                                            shattercane   Sorghum bicolor   SHC                                           wild oat      Avena fatua       WO                                            broadleaf signalgrass                                                                       Brachiaria platyphylla                                                                          BSG                                           green foxtail Setaria viridis   FT                                            yellow nutsedge                                                                             Cyperus esculentus                                                                              YNS                                           Broadleaf Weeds                                                               sicklepod     Cassia obtusifolia                                                                              SP                                            sesbania      Sesbanis exaltata SESB                                          cocklebur     Xanthium pensylvanicum                                                                          CB                                            annual morningglory                                                                         Ipomea purpurea   AMG                                           velvetleaf    Abuliton theoprasti                                                                             VL                                            mustard       Brassica juncea   MD                                            curly dock    Rumex crispus     CD                                            Crop plants were also planted at the same time. These were as                 follows:                                                                      CROP PLANTS                                                                   sugarbeets    Beta vulgaris     SB                                            soybeans      Glycine max       SOY                                           rice          Oryzae sativa     RC                                            cotton        Gossypium hirsutum                                                                              COT                                           corn          Zea mays          CN                                            wheat         Triticum aestivum WH                                            milo          Sorghum bicolor   ML                                            ______________________________________                                    

Sufficient seeds were planted to produce several seedlings per inch ineach row. The flats were then placed in a greenhouse maintained at 70°to 85° F. (21° to 30° C.) and watered daily by sprinkler.

In pre-emergent testing (PES) the herbicide is incorporated into thesoil prior to planting of the seeds.

In post-emergent testing (POST) chemical application is made by spraying12 days after planting. The spray solution is prepared by dissolving 84mg of herbicide compound in 20 ml of acetone containing 0.5% Tween® 20(polyoxysorbitan monolaurate), then adding 20 ml of water to theresulting solution. The solution is sprayed at 25 gallon/acre. Otherrates are achieved by varying the solution concentration and/or the rateof spray.

Approximately 12-14 days after treatment, the degree of weed control wasestimated and recorded as percentage control compared to the growth ofthe same species in an untreated check flat of the same age. The ratingscale ranges from 0 to 100%, where 0 equals no effect with plant growthequal to the untreated control, and 100 equals complete kill.

The results are listed in Tables I and II below.

                                      TABLE I                                     __________________________________________________________________________    HERBICIDE TEST RESULTS                                                        Compound                                                                            Application                                                                              Weed Species                                                 Number                                                                              Rate (lb/A)                                                                         Method                                                                             FT WG WO AMG VL MD CD YNS                                    __________________________________________________________________________    1     4.00  PES  0  0  0  0   0  0  0  0                                            4.00  POST 0  0  0  30  40 100                                                                              20 0                                      2     4.00  PES  0  0  0  0   0  0  0  0                                            4.00  POST 100                                                                              20 30 100 90 100                                                                              100                                                                              0                                      3     4.00  PES  0  0  0  0   30 70 0  0                                            4.00  POST 100                                                                              30 90 100 100                                                                              100                                                                              100                                                                              0                                      4     4.00  PES  0  0  0  0   100                                                                              100                                                                              60 0                                            4.00  POST 100                                                                              0  0  60  70 100                                                                              100                                                                              0                                      5     4.00  PES  70 20 55 100 100                                                                              100                                                                              70 0                                            4.00  POST 100                                                                              100                                                                              90 100 100                                                                              100                                                                              100                                                                              0                                      6     4.00  PES  20 15 25 0   0  40 20 0                                            4.00  POST 20 20 0  30  0  100                                                                              0  0                                      7     4.00  PES  0  0  0  0   0  100                                                                              0  0                                            4.00  POST 0  15 0  50  80 100                                                                              0  0                                      8     4.00  PES  20 15 0  10  0  80 0  0                                            4.00  POST 70 0  0  100 100                                                                              100                                                                              60 0                                      9     4.00  PES  0  0  0  0   0  0  0  0                                            4.00  POST 75 40 0  100 80 100                                                                              100                                                                              0                                      10    4.00  *PES 0  0  0  0   0  0  0  0                                            4.00  POST 80 20 0  40  30 100                                                                              70 0                                      11    4.00  PES  0  0  0  0   0  0  0  0                                            4.00  POST 100                                                                              20 30 70  70 100                                                                              90 0                                      12    4.00  PES  0  0  0  0   0  0  0  0                                            4.00  POST 100                                                                              30 40 100 100                                                                              95 90 0                                      13    4.00  PES  0  25 0  15  0  100                                                                              100                                                                              0                                            4.00  POST 100                                                                              20 0  100 35 100                                                                              100                                                                              0                                      14    4.00  PES  0  0  0  0   0  0  0  0                                            4.00  POST 15 0  0  15  100                                                                              100                                                                              0  0                                      15    4.00  PES  15 65 20 45  70 100                                                                              20 0                                            4.00  POST 70 35 30 100 90 100                                                                              75 0                                      16    4.00  PES  100                                                                              100                                                                              90 98  100                                                                              100                                                                              100                                                                              10                                           4.00  POST 100                                                                              100                                                                              100                                                                              100 100                                                                              100                                                                              100                                                                              35                                     17    4.00  PES  0  0  0  0   0  0  95 N                                            4.00  POST 50 25 0  70  80 100                                                                              100                                                                              0                                      18    4.00  PES  80 80 0  85  95 100                                                                              95 N                                            4.00  POST 100                                                                              100                                                                              100                                                                              100 100                                                                              100                                                                              100                                                                              0                                      19    4.00  PES  85 90 0  75  85 100                                                                              95 N                                            4.00  POST 100                                                                              95 100                                                                              100 100                                                                              100                                                                              100                                                                              0                                      20    4.00  PES  40 15 0  0   40 90 90 N                                            4.00  POST 90 40 10 100 95 100                                                                              100                                                                              0                                      21    4.00  PES  25 0  0  0   0  0  0  0                                            4.00  POST 100                                                                              40 0  100 50 90 90 0                                      22    4.00  PES  0  0  0  0   0  0  0  0                                            4.00  POST 90 25 0  95  95 95 90 0                                      23    4.00  PES  25 0  0  80  80 100                                                                              100                                                                              N                                            4.00  POST 95 95 95 100 100                                                                              100                                                                              100                                                                              0                                      24    4.00  PES  100                                                                              100                                                                              25 95  90 100                                                                              100                                                                              0                                            4.00  POST 100                                                                              100                                                                              100                                                                              100 100                                                                              100                                                                              100                                                                              N                                      25    4.00  PES  100                                                                              100                                                                              50 100 100                                                                              100                                                                              90 0                                            4.00  POST 100                                                                              100                                                                              100                                                                              100 100                                                                              100                                                                              100                                                                              N                                      26    4.00  PES  100                                                                              100                                                                              50 100 100                                                                              100                                                                              90 0                                            4.00  POST 100                                                                              100                                                                              100                                                                              100 100                                                                              100                                                                              100                                                                              N                                      27    4.00  PES  65 0  0  30  35 100                                                                              0  0                                            4.00  POST 100                                                                              25 85 100 95 100                                                                              85 0                                      28    4.00  PES  65 70 0  75  15 100                                                                              85 0                                            4.00  POST 50 25 0  85  35 95 75 0                                      29    4.00  PES  85 25 0  0   0  100                                                                              100                                                                              0                                            4.00  POST 100                                                                              100                                                                              50 95  100                                                                              100                                                                              100                                                                              0                                      30    4.00  PES  85 25 0  0   0  100                                                                              100                                                                              0                                            4.00  POST 100                                                                              100                                                                              50 95  100                                                                              100                                                                              100                                                                              0                                      31    4.00  PES  100                                                                              100                                                                              50 90  100                                                                              100                                                                              100                                                                              0                                            4.00  POST 100                                                                              100                                                                              100                                                                              100 100                                                                              100                                                                              85 50                                     32    4.00  PES  100                                                                              100                                                                              0  85  100                                                                              100                                                                              100                                                                              0                                            4.00  POST 100                                                                              100                                                                              95 100 100                                                                              100                                                                              95 0                                      34    4.00  PES  100                                                                              0  0  0   95 100                                                                              90 0                                            4.00  POST 100                                                                              20 20 100 85 100                                                                              85 0                                      35    4.00  PES  95 90 0  60  100                                                                              100                                                                              90 0                                            4.00  POST 95 25 0  100 100                                                                              100                                                                              90 0                                      37    4.00  PES  100                                                                              95 0  100 100                                                                              100                                                                              100                                                                              0                                            4.00  POST 100                                                                              100                                                                              100                                                                              100 100                                                                              100                                                                              100                                                                              0                                      38    4.00  PES  0  0  0  0   0  0  0  0                                            4.00  POST 50 35 10 35  35 100                                                                              100                                                                              0                                      39    4.00  PES  0  0  0  0   0  100                                                                              100                                                                              0                                            4.00  POST 100                                                                              100                                                                              25 100 90 100                                                                              90 0                                      40    4.00  PES  0  0  0  0   0  25 0  0                                            4.00  POST 20 20 100                                                                              50  60 100                                                                              90 0                                      41    4.00  PES  0  0  0  10  70 100                                                                              100                                                                              0                                            4.00  POST 70 60 0  100 85 100                                                                              100                                                                              0                                      42    4.00  PES  0  0  0  20  0  100                                                                              85 0                                            4.00  POST 90 50 40 100 100                                                                              100                                                                              100                                                                              0                                      43    4.00  PES  100                                                                              100                                                                              35 100 100                                                                              100                                                                              100                                                                              0                                            4.00  POST 100                                                                              100                                                                              95 100 100                                                                              100                                                                              100                                                                              35                                     44    4.00  PES  95 95 0  40  50 90 85 0                                            4.00  POST 100                                                                              100                                                                              100                                                                              100 100                                                                              100                                                                              100                                                                              20                                     47    4.00  PES  90 60 15 25  30 100                                                                              100                                                                              0                                            4.00  POST 100                                                                              70 30 100 N  100                                                                              100                                                                              0                                      48    4.00  PES  0  0  0  0   0  0  0  0                                            4.00  POST 60 20 10 100 80 100                                                                              15 0                                      49    4.00  PES  0  0  0  0   0  0  0  0                                            4.00  POST 20 20 0  30  90 100                                                                              100                                                                              0                                      50    4.00  PES  0  0  0  0   0  0  50 0                                            4.00  POST 0  0  0  60  100                                                                              100                                                                              80 0                                      __________________________________________________________________________

    TABLE 2      Cmpd. Application  Weed Species Crop Species No. Rate (lb/A) Method DB     FT ARG WG SHC WO BSG AMG SESB VL SP MD YNS CB SOY WH ML RC SB CN     COT       5 0.25 PES N N N N N N N 0 10 0 0 0 0 0 0 0 0 0 0 0 0  0.50     PES N N N N N N N 30 60 40 0 100 0 0 20 0 0 0 20 0 0  1.00 PES N N N N N     N N 40 75 90 60 95 10 0 50 0 10 0 100 20 10  2.00 PES 10 70 10 20 20 30     80 95 80 60 60 100 0 0 60 0 0 0 80 30 50  0.25 POST 60 100 20 10 10 10 0     100 80 100 80 100 10 N 40 10 20 30 100 30 100  0.50 POST 40 100 20 10 10     30 30 100 90 70 60 100 10 N 100 30 40 60 100 70 100  1.00 POST 40 100 50     20 20 30 40 100 95 80 90 100 10 100 100 60 100 100 100 100 100  2.00     POST 50 100 70 90 40 80 80 100 95 100 90 100 10 100 100 60 100 100 100     100 100 17 0.10 PES 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0  0.25 PES     10 20 10 10 0 0 0 20 50 30 0 90 0 0 30 0 0 0 50 0 0  0.50 PES 40 100 40     30 10 60 50 60 70 100 30 100 50 20 40 0 10 10 100 0 20  1.00 PES 60 100     70 80 60 50 70 100 90 100 60 100 10 0 60 0 30 20 100 30 60  2.00 PES 60     100 60 100 60 60 100 100 70 60 60 100 30 0 60 30 50 40 100 50 100  0.10     POST 20 20 40 10 10 10 10 70 80 100 90 100 0 100 80 20 10 40 100 60 100     0.25 POST 60 20 80 30 10 20 20 100 100 100 80 100 10 N 100 30 20 80 100     60 100  0.50 POST 60 100 70 30 50 50 80 100 100 100 80 100 10 100 100 30     100 100 100 100 100  1.00 POST 70 100 70 30 50 30 80 100 100 100 100 100     30 100 100 40 100 100 100 100 100  2.00 POST 70 100 100 100 100 100 100     100 100 100 100 100 30 100 100 100 100 100 100 100 100 25 2.00 PES 100     100 60 100 80 25 50 25 70 100 30 100 0 100 35 30 45 40 100 20 0  1.00     PES 80 100 60 100 80 10 30 15 35 50 30 100 0 N 10 0 15 10 95 20 0  0.50     PES 100 40 40 20 20 10 20 5 25 30 10 100 0 N 10 0 0 0 100 10 0  0.25 PES     N N N N N N N 0 10 30 0 0 0 0 0 0 0 0 90 0 0  2.00 POST 100 100 100 100     100 95 100 90 100 100 90 100 0 100 100 70 100 100 100 100 100  1.00 POST     100 100 100 100 90 80 100 100 100 98 70 100 0 N 100 25 100 100 100 100     90  0.50 POST 98 100 100 100 90 80 85 100 100 90 70 100 0 N 90 30 45 100     100 90 100  0.25 POST 80 100 100 50 40 30 25 100 100 100 20 100 0 100 60     0 15 60 100 80 100 27 2.00 PES 100 100 100 100 100 60 80 100 100 100 70     100 0 100 100 40 50 40 100 70 0  1.00 PES 100 100 75 90 85 60 70 100 100     100 45 100 0 100 70 30 30 15 100 80 0  0.50 PES 40 60 40 50 65 10 60 15     30 65 0 35 0 N 60 0 15 20 100 10 0  0.25 N N N N N N N N 0 20 20 0 20 0     N 0 0 0 10 30 0 0  2.00 POST 100 100 100 100 100 100 100 100 100 100 100     100 0 N 100 100 100 100 100 100 100  1.00 POST 100 100 95 75 100 100 100     100 100 100 60 100 0 100 100 40 65 98 100 65 100  0.50 POST 85 85 80 20     40 55 85 100 100 100 60 100 0 N 80 15 20 98 100 25 85  0.25 POST 60 75     30 10 15 10 15 90 80 80 45 98 0 N 80 0 20 50 100 10 50 28 2.00 POST 50     100 50 35 0 15 15 100 100 100 80 100 0 100 100 30 0 40 100 15 100  1.00     POST 50 90 50 30 0 0 0 100 100 100 20 100 0 N 100 30 20 40 100 15 100     0.50 POST N N N N N N N 85 95 90 20 100 0 N 100 0 0 20 100 0 90  0.25     POST N N N N N N N 90 70 90 0 97 0 N 30 0 0 0 70 0 90 30 2.00 PES 20 70     15 30 30 0 15 50 70 100 0 100 0 100 30 0 20 0 100 0 15  2.00 POST 100     100 100 100 100 80 100 100 100 100 100 100 0 100 100 80 70 85 100 85 95     1.00 POST 90 100 100 100 65 20 80 100 100 100 90 100 0 100 100 80 50 80     100 40 100  0.50 POST 80 100 100 100 65 20 70 100 100 100 85 100 0 100     100 40 50 80 100 40 90  0.25 POST 90 100 100 75 80 20 70 100 100 100 70     100 0 100 98 40 20 25 100 35 100 31 2.00 PES 100 100 98 100 100 95 95     100 100 100 25 100 0 100 100 35 45 45 100 50 0  1.00 PES 100 100 98 100     100 90 85 100 95 100 20 100 0 100 70 15 30 35 100 50 20  0.50 PES 90 100     90 100 100 40 20 30 35 40 0 100 0 15 30 30 20 20 30 0 0  0.25 PES N N N     N N N N 10 15 20 0 90 0 0 20 20 0 0 30 0 0  2.00 POST 100 100 100 100     100 100 100 100 100 100 100 100 60 N 100 100 100 100 100 100 100  1.00     POST 100 100 100 100 100 100 100 100 100 98 100 60 N 100 75 100 100 100     100 100 100  0.50 POST 100 100 100 90 100 80 98 100 100 90 85 100 0 N     100 20 00 100 100 100 100  0.25 POST 90 100 100 90 100 45 90 100 100 100     85 100 0 N 100 30 100 90 100 90 100 32 2.00 PES 100 100 90 100 100 35 60     70 100 100 90 100 15 100 40 10 60 50 100 30 60  1.00 PES 90 100 90 100     100 20 35 20 85 100 25 100 0 100 40 15 25 20 100 0 15  0.50 PES 60 90 35     60 70 10 15 20 85 100 0 95 0 N 40 0 25 20 100 0 0  0.25 PES 20 30 0 30     25 0 0 0 15 20 0 85 0 0 15 0 10 0 30 0 0  2.00 POST 80 100 100 100 100     65 100 100 100 100 100 100 0 100 100 100 100 100 100 100 100  1.00 POST     80 100 100 100 100 60 98 100 98 85 100 100 0 N 100 55 90 100 100 100 100      0.50 POST 70 100 100 90 90 45 85 100 95 100 100 100 0 100 100 50 80 100     100 100 100  0.25 POST 70 100 80 35 60 15 80 100 95 100 90 100 0 100 100     60 35 65 100 85 100 37 2.00 PES 80 100 50 95 95 30 90 90 95 100 95 100 0     100 85 40 45 40 100 20 40  1.00 PES 90 100 40 95 100 15 85 95 95 100 90     100 0 100 40 15 35 30 100 15 15  0.50 PES 25 100 20 60 80 20 25 65 90     100 25 100 0 100 35 0 10 15 70 0 15  0.25 PES N N N N N N N 15 65 65 20     85 0 0 30 0 0 0 30 0 0  2.00 POST 85 100 100 100 100 85 100 100 100 100     98 100 30 N 100 30 100 100 100 100 100  1.00 POST 85 100 100 100 100 70     100 100 100 100 65 100 0 N 100 30 100 100 100 100 100  0.50 POST 90 100     100 100 100 60 100 100 100 100 70 100 0 100 100 30 90 100 100 70 100     0.25 POST 65 100 100 100 90 50 90 100 100 90 60 100 0 100 100 25 70 100     100 45 100 47 2.00 PES 20 90 40 60 15 0 0 30 95 40 35 100 0 N 80 0 0 0 0     0 10  1.00 PES 0 60 0 25 0 0 0 15 85 20 0 70 0 N 80 0 0 0 0 0 0  2.00     POST 0 100 0 0 0 0 65 100 100 100 100 100 0 N 100 20 40 0 100 0 85  1.00     POST 0 90 0 0 0 0 50 100 100 100 100 100 0 N 100 0 45 0 100 0 65  0.50     POST 0 90 0 0 0 0 50 100 100 100 100 100 0 N 100 0 30 0 100 0 65  0.25     POST 0 20 0 0 0 0 30 75 100 100 90 60 0 N 60 0 20 0 100 0 35 48 2.00     POST 15 0 0 0 0 0 0 100 100 0 100 100 0 N 80 60 60 100 100 40 40  0.50     POST 10 0 0 0 0 0 0 80 100 0 65 100 0 N 80 30 25 30 100 40 40  0.25 POST     N N N N N N N 75 30 0 10 45 0 N 40 0 10 25 100 10 15 49 2.00 POST 15 30     0 0 0 0 0 75 100 80 20 100 0 N 75 0 20 0 100 20 40  1.00 POST 0 0 0 0 15     0 20 50 100 80 20 100 0 N 40 0 15 0 100 0 45  0.50 POST 0 0 0 0 0 0 0 30     70 15 20 100 0 N 35 0 10 0 100 0 40  0.25 POST 0 0 0 0 0 0 0 30 60 15 10     100 0 N 40 0 0 0 55 0 25

METHODS OF APPLICATION

The herbicidal compositions of the present invention are useful incontrolling the growth of undesirable vegetation by pre-emergence orpost-emergence application to the locus where control is desired,including pre-plant and post-plant soil incorporation as well as surfaceapplication. The compositions are generally embodied in formulationssuitable for convenient application. Typical formulations containadditional ingredients or diluent carriers which are either inert oractive. Examples of such ingredients or carriers are water, organicsolvents, dust carriers, granular carriers, surface active agents, oiland water, wateroil emulsions, wetting agents, dispersing agents, andemulsifying agents. The herbicidal formulations generally take the formof dusts, emulsifiable concentrates, granules and pellets, ormicrocapsules.

A. DUSTS

Dusts are dense powder compositions which are intended for applicationin dry form. Dusts are characterized by their free-flowing and rapidsettling properties so that they are not readily windborne to areaswhere their presence is not desired. They contain primarily an activematerial and a dense, free-flowing, solid carrier.

Their performance is sometimes aided by the inclusion of a wettingagent, and convenience in manufacture frequently demands the inclusionof an inert, absorptive grinding aid. For the dust compositions of thisinvention, the inert carrier may be either of vegetable or mineralorigin, the wetting agent is preferably anionic or nonionic, andsuitable absorptive grinding aids are of mineral origin.

Suitable classes of inert solid carriers for use in the dustcompositions are those organic or inorganic powders which possess highbulk density and are very free-flowing. They are also characterized bylow surface area and poor liquid absorptivity. Suitable grinding aidsare natural clays, diatomaceous earths, and synthetic mineral fillersderived from silica or silicate. Among ionic and nonionic wettingagents, the most suitable are the members of the group known to the artas wetting agents and emulsifiers. Although solid agents are preferredbecause of ease of incorporation, some liquid nonionic agents are alsosuitable in the dust formulations.

Preferred dust carriers are micaceous talcs, pyrophyllite, dense kaolinclays, tobacco dust and ground calcium phosphate rock.

Preferred grinding aids are attapulgite clay, diatomaceous silica,synthetic fine silica and synthetic calcium and magnesium silicates.

Most preferred wetting agents are alkylbenzene and alkyl-naphthalenesulfonates, sulfated fatty alcohols, amines or acid amides, long chainacid esters of sodium isothionate, esters of sodium sulfosuccinate,sulfated or sulfonated fatty acid esters, petroleum sulfonates,sulfonated vegetable oils, and ditertiary acetylenic glycols. Preferreddispersants are methyl cellulose, polyvinyl alcohol, lignin sulfonates,polymeric alkylnaphthalene sulfonates, sodium naphthalenesulfonate,polymethylene bisnaphthalenesulfonate, and sodium-N-methyl-N-(long chainacid) taurates.

The inert solid carriers in the dusts of this invention are usuallypresent in concentrations of from about 30 to 90 weight percent of thetotal composition. The grinding aid will usually constitute 5 to 50weight percent of the compositions, and the wetting agent willconstitute from about 0 to 1.0 weight percent of the composition. Dustcompositions can also contain other surfactants such as dispersingagents in concentrations of up to about 0.5 weight percent, and minoramounts of anticaking and antistatic agents. The particle size of thecarrier is usually in the range of 30 to 50 microns.

B. EMULSIFIABLE CONCENTRATES

Emulsifiable concentrates are usually solutions of the active materialsin nonwater-miscible solvents together with an emulsifying agent. Priorto use, the concentrate is diluted with water to form a suspendedemulsion of solvent droplets.

Typical solvents for use in emulsifiable concentrates include weed oils,chlorinated hydrocarbons, and nonwater-miscible ethers, esters, andketones.

Typical emulsifying agents are anionic or nonionic sufactants, ormixtures of the two. Examples include long-chain alkyl or mercaptanpolyethoxy alcohols, alkylaryl polyethoxy alcohols, sorbitan fatty acidesters, polyoxyethylene ethers with sorbitan fatty acid esters,polyoxyethylene glycol esters with fatty or rosin acids, fatty alkylolamide condensates, calcium and amine salts of fatty alcohol sulfates,oil soluble petroleum sulfonates, or preferably mixtures of theseemulsifying agents. Such emulsifying agents will comprise from about 1to 10 weight percent of the total composition.

Thus, emulsifiable concentrates of the present invention will consist offrom about 15 to about 50 weight percent active material, about 40 to 82weight percent solvent, and about 1 to 10 weight percent emulsifier.Other additives such as spreading agents and stickers can also beincluded.

C. GRANULES AND PELLETS

Granules and pellets are physically stable, particulate compositionscontaining the active ingredients adhering to or distributed through abasic matrix of a coherent, inert carrier with microscopic dimensions. Atypical particle is about 1 to 2 millimeters in diameter. Surfactantsare often present to aid in leaching of the active ingredient from thegranule or pellet.

The carrier is preferably of mineral origin, and generally falls withinone of two types. The first are porous, absorptive, preformed granules,such as preformed and screened granular attapulgite or heat expanded,granular, screened vermiculite. On either of these, a solution of theactive agent can be sprayed and will be absorbed at concentrations up to25 weight percent of the total weight. The second, which are alsosuitable for pellets, are initially powdered kaolin clays, hydratedattapulgite, or bentonite clays in the form of sodium, calcium, ormagnesium bentonites. Water-soluble salts, such as sodium salts, mayalso be present to aid in the disintegration of granules or pellets inthe presence of moisture. These ingredients are blended with the activecomponents to give mixtures that are granulated or pelleted, followed bydrying, to yield formulations with the active component distributeduniformly throughout the mass. Such granules and pellets can also bemade with 25 to 30 weight percent active component, but more frequentlya concentration of about 10 weight percent is desired for optimumdistribution. The granular compositions of this invention are mostuseful in a size range of 15-30 mesh.

The surfactant is generally a common wetting agent of anionic ornonionic character. The most suitable wetting agents depend upon thetype of granule used. When preformed granules are sprayed with activematerial in liquid form the most suitable wetting agents are nonionic,liquid wetters miscible with the solvent. These are compounds mostgenerally known in the art as emulsifiers, and comprise alkylarylpolyether alcohols, alkyl polyether alcohols, polyoxyethylene sorbitanfatty acid esters, polyethylene glycol esters with fatty or rosin acids,fatty alkylol amide condensates, oil solution petroleum or vegetable oilsulfonates, or mixtures of these. Such agents will usually comprise upto about 5 weight percent of the total composition.

When the active ingredient is first mixed with a powdered carrier andsubsequently granulated, or pelleted, liquid nonionic wetters can stillbe used, but it is usually preferable to incorporate at the mixing stageone of the solid, powdered anionic wetting agents such as thosepreviously listed for the wettable powders. Such agents will comprisefrom about 0 to 2 weight percent of the total composition.

Thus, the preferred granular or pelleted formulations of this inventioncomprise about 5 to 30 percent by weight active material, about 0 to 5weight percent wetting agent, and about 65 to 95 weight percent inertmaterial carrier, as these terms are used herein.

D. MICROCAPSULES

Microcapsules consist of fully enclosed droplets or granules containingthe active materials, in which the enclosing material is an inert porousmembrane, arranged to allow escape of the enclosed materials to thesurrounding medium at controlled rates over a specified period.Encapsulated droplets are typically about 1 to 50 microns in diameter.

The enclosed liquid typically constitutes about 50 to 95% of the weightof the entire capsule, and may contain a small amount of solvent inaddition to the active materials.

Encapsulated granules are characterized by porous membranes sealing theopenings of the granule carrier pores, trapping the liquid containingthe active components inside for controlled release. A typical granulesize ranges from 1 millimeter to 1 centimeter in diameter. Inagricultural useage, the granule size is generally about 1 to 2 ml indiameter. Granules formed by extrusion, agglomeration, or prilling areuseful in the present invention as well as materials in their naturallyoccurring form. Examples of such carriers are vermiculite, sintered claygranules, kaolin, attapulgite clay, sawdust, and granular carbon.

Useful encapsulating materials include natural and synthetic rubbers,cellulosic materials, styrene-butadiene copolymers, polyacrylonitriles,polyacrylates, polyesters, polyamides, polyurethanes, and starchxanthates.

E. IN GENERAL

Each of the above formulations can be prepared as a package containingthe herbicide together with the other ingredients of the formulation(diluents, emulsifiers, surfactants, etc.). The formulations can also beprepared by a tank mix method, in which the ingredients are obtainedseparately and combined at the grower site.

In general, any conventional method of application can be used. Thelocus of application can be soil, seeds, seedlings, or the actualplants, as well as flooded fields. Post-emergent application ispreferred. Dusts and liquid compositions can be applied by the use ofpowder dusters, boom and hand sprayers, and spray dusters. Thecompositions can also be applied from airplanes as dusts and spraysbecause they are effective in very low dosages. In order to modify orcontrol the growth of germinating seeds or emerging seedlings, as atypical example, the dust and liquid compositions are applied to thesoil according to conventional methods and are distributed in the soilto a depth of at least one-half inch below the soil surface. It is notnecessary that the phytotoxic compositions be admixed with the soilparticles. Instead, these compositions can be applied merely by sprayingor sprinkling the surface of the soil. The phytotoxic compositions ofthis invention can also be applied by addition to irrigation watersupplied to the field to be treated. This method of application permitsthe penetration of the compositions into the soil as the water isabsorbed therein. Dust compositions, granular compositions or liquidformulations applied to the surface of the soil can be distributed belowthe surface of the soil by conventional means such as discing, draggingor mixing operations.

The herbicide compositions can also be applied to the soil throughirrigation systems. According to this technique, the compositions areadded directly to irrigation water immediately prior to irrigation ofthe field. This technique is applicable in all geographical areasregardless of rainfall, since it permits supplementation of the naturalrainfall at critical stages of plant growth. In a typical application,the concentration of the herbicide composition in the irrigation waterwill range from about 10 to 150 parts per million by weight. Theirrigation water can be applied by the use of sprinkler systems, surfacefurrows, or flooding. Such application is most effectively done beforethe weeds germinate, either early in the spring prior to germination orwithin two days after cultivation of the field.

The amount of the present composition which constitutes a herbicidallyeffective amount depends upon the nature of the seeds or plants to becontrolled. The rate of application of active ingredient varies fromabout 0.01 to about 50 pounds per acre, preferably about 0.1 to about 25pounds per acre with the actual amount depending on the overall cost andthe desired results. It will be readily apparent to one skilled in theart that compositions exhibiting lower herbicidal activity will requirea higher dosage than more active compounds for the same degree ofcontrol.

What is claimed is:
 1. A pyrimidine having the formula ##STR78## whereinA is oxygen or sulfur;M is N; X is hydrogen, lower alkyl, halo, methoxy,alkoxy, C₁ -C₃ alkylthio, cyano, carbomethoxy or trifluoromethyl;##STR79## R' is C₁ -C₈ straight, branched-chain or halo-alkyl, phenyl orhalophenyl; and R is hydrogen, C₁ -C₈ straight or branched chain alkyl,C₅ or C₆ cycloalkyl or phenyl or halophenyl; and n is zero to two.
 2. Aherbicidal composition which comprises a carrier and a herbicidallyeffective amount of a pyrimidine having the formula ##STR80## wherein Ais oxygen or sulfur;M is N; X is hydrogen, lower alkyl, halo, methoxy,alkoxy, C₁ -C₃ alkylthio, cyano, carbomethoxy or trifluoromethyl;##STR81## R' is C₁ -C₈ straight, branched-chain or halo-alkyl, phenyl orhalophenyl; and R is hydrogen, C₁ -C₈ straight or branched chain alkyl,C₅ or C₆ cycloalkyl or phenyl or halophenyl; and n is zero to two.
 3. Amethod for controlling undesirable weed pests which comprises applyingto the locus where control is desired a herbicidally effective amount ofa pyrimidine compound having the formula ##STR82## wherein A is oxygenor sulfur;M is N; X is hydrogen, lower alkyl, halo, methoxy, alkoxy, C₁-C₃ alkylthio, cyano, carbomethoxy or trifluoromethyl; ##STR83## R' isC₁ -C₈ straight, branched-chain or halo-alkyl, phenyl or halophenyl; andR is hydrogen, C₁ -C₈ straight or branched chain alkyl, C₅ or C₆cycloalkyl or phenyl or halophenyl; and n is zero to two.